A corrosion and waterproof flexible sensor and a preparation method thereof

Abstract

The present application relates to a kind of corrosion and waterproof flexible sensor and its preparation method, including flexible substrate, encapsulation area and electrode layer, flexible substrate is provided with electrode layer and encapsulation area, the encapsulation area has microstructure, increase the specific surface area between encapsulation area and flexible substrate and electrode layer, microstructure includes convex ridge, several convex ridges are arranged in parallel or cross, convex ridge protrudes from flexible substrate, and convex ridge is arranged around electrode layer.Effective increase of specific surface area between encapsulation area and flexible substrate and flexible electrode layer is achieved by using innovative design encapsulation microstructure, and the encapsulation density between electrode layer and electrode layer is enhanced;The encapsulation process is heat-pressed in vacuum environment, and encapsulation material is fully filled in convex and concave ridge microstructure after melting, to realize the firm combination between substrate layer and electrode layer;Cross-linking can be achieved with substrate and electrode layer material, and good conformal attachment is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of flexible sensor, in particular to a kind of anticorrosive waterproof flexible sensor and preparation method thereof. BACKGROUND

[0002] With the wide application of flexible sensor, higher requirements for its corrosion resistance and waterproof performance are also put forward. But there are still some challenges in the actual application of flexible sensor in terms of corrosion resistance and moisture resistance, and the long-term durability and environmental stability of flexible sensor still need to be improved. The stability of flexible sensor against environmental interference such as corrosion resistance and moisture resistance is closely related to the interface packaging effect between flexible substrate and electrode layer, in addition to the stability of flexible substrate material and sensing material in the environment. One of the main reasons why the current flexible sensor device is not corrosion resistant and waterproof is that the packaging between the flexible substrate (polyethylene terephthalate (PET), polyimide (PI), polytetrafluoroethylene (FEP) and electrode layer is not dense and firm, and the density and firmness of the interface packaging between the flexible substrate and the electrode layer are closely related to the corrosion and waterproof performance of the sensor. SUMMARY

[0003] In view of the existing challenges, the present application innovatively improves from three aspects of flexible packaging material, packaging structure and packaging process, and provides a flexible sensor capable of realizing corrosion and waterproof and a preparation method thereof.

[0004] The specific technical solutions are as follows: an anticorrosive waterproof flexible sensor, comprising a flexible substrate, a packaging area and an electrode layer, the flexible substrate is provided with the electrode layer and the packaging area, the packaging area has a microstructure, which increases the specific surface area between the packaging area and the flexible substrate and the electrode layer, the microstructure comprises convex ridges, a plurality of convex ridges are arranged in parallel or intersected, the convex ridges protrude from the flexible substrate, and the convex ridges are arranged around the electrode layer.

[0005] In some embodiments, the width-depth ratio of the convex ridge is 1.4 to 83.3, and the convex ridge gap is 0.1 to 1 mm.

[0006] In some embodiments, the convex ridges are arranged around.

[0007] In some embodiments, the width-depth ratio of the convex ridge is 1.4, and the convex ridge gap is 0.1 mm.

[0008] In some embodiments, the width-depth ratio of the convex ridge is 83.3, and the convex ridge gap is 1 mm.

[0009] In some embodiments, the packaging material of the packaging area adopts any one of epoxy group, isocyanate group or hydroxyl group.

[0010] A preparation method of an anticorrosive waterproof flexible sensor, comprising the following steps:

[0011] S1: cutting the flexible encapsulation material into a pattern required for encapsulation;

[0012] S2: sequentially attaching the patterned encapsulation material to the encapsulation area of the electrode layer substrate;

[0013] S3: aligning and attaching the electrode layer substrate with the attached encapsulation material to the flexible substrate and compacting using a roller;

[0014] S4: placing the compacted electrode layer substrate and the flexible substrate as a whole under a hot press device for hot pressing;

[0015] S5: placing the device in a vacuum thermal environment for a certain period of time and then taking it out.

[0016] In some embodiments, in step S4, during hot pressing, double-sided hot pressing is performed at a temperature of 80-150 degrees for 5-60 seconds.

[0017] In some embodiments, in step S5, the device is placed in a vacuum thermal environment with a pressure of -0.01 to -1.2 MPa and a temperature of 80 to 150 degrees, and the device is placed in the vacuum thermal environment for 10-60 minutes and then taken out.

[0018] In some embodiments, before step S1, a plurality of parallel or cross-arranged microstructures are made on the flexible substrate of the corrosion-resistant and waterproof flexible sensor, the width-depth ratio of the convex ridges in the microstructures is 1.4 to 83.3, and the gap between the convex ridges is 0.1 to 1 mm.

[0019] Technical effects of the present application: The corrosion-resistant and waterproof flexible sensor and the preparation method thereof have the following technical advantages: (1) selecting an encapsulation material with a modulus suitable for the flexible substrate and capable of cross-linking with the substrate and the electrode layer material to achieve good conformal attachment. (2) innovatively designing encapsulation microstructures to effectively increase the specific surface area between the encapsulation area and the flexible substrate and the flexible electrode layer, and enhance the encapsulation density between the electrode layers. (3) Hot pressing treatment in a vacuum environment to make the encapsulation material melt and fully fill in the convex-concave ridge microstructures, achieving firm bonding between the substrate layer and the electrode layer. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the description of the specific embodiments or the prior art. Obviously, the drawings described below are some embodiments of the present application, and those skilled in the art can also obtain other drawings based on these drawings without creative labor.

[0021] Figure 1 is a schematic diagram of a corrosion-resistant and waterproof flexible sensor according to an embodiment of the present application.

[0022] Figure 2 is the present invention Figure 1 is a magnified view of the convex ridge of part A in the present invention. DETAILED DESCRIPTION

[0023] The technical solutions of the present application will be described clearly and completely below in conjunction with the drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0024] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", "third" are only for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0025] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0026] The specific embodiments of the present application will be described in detail below in conjunction with the drawings. It should be understood that the specific embodiments described here are only used to illustrate and explain the present application, and are not used to limit the present application.

[0027] Embodiment one

[0028] As Figure 1 and Figure 2As shown, the anti-corrosion and waterproof flexible sensor of the embodiment comprises a flexible substrate 1 and an electrode layer 2, and the flexible substrate 1 has an encapsulation area 3. The encapsulation area 3 has a microstructure 4, which increases the specific surface area between the encapsulation area 3 and the flexible substrate 1 and the electrode layer 2. The microstructure 4 comprises convex ridges 41, and a plurality of convex ridges 41 are arranged in parallel or intersected. The convex ridges 41 protrude from the encapsulation area 3, and the electrode layer 2 is arranged around the convex ridges 41. In the above technical solution, the specific surface area between the encapsulation area and the flexible substrate and the electrode layer can be effectively increased by arranging the microstructure 4, the adhesion of the encapsulation material can be enhanced, the encapsulation density between the flexible substrate and the electrode layer can be enhanced, and the optimization of the encapsulation stability and the environmental interference resistance is very effective. The microstructure of the embodiment is a concave-convex ridge microstructure, and a plurality of convex ridges 41 have grooves therebetween.

[0029] In the embodiment, the width-depth ratio of the convex ridges 41 is 1.4 to 83.3, and the gap between the convex ridges 41 is 0.1 to 1 mm. The convex ridges with the above parameters can have better adhesion and encapsulation density. Higher than the preferred range causes the convex ridge microstructure to be too wide and the concave ridge to be too shallow, and the effect of improving the specific surface area of the encapsulation material and enhancing the adhesion is not obvious. Lower than the preferred range causes the convex ridge microstructure to be too deep, and the encapsulation material is easy to be insufficiently contacted with the flexible substrate and encapsulated not densely. The sensor higher or lower than the preferred range is found to have a trace of liquid immersion in a solution with a pH value of 4 after being soaked for 60 days, and the shear strength test is <1 kg / cm 2 . The convex ridges 41 are arranged around.

[0030] In the embodiment, the encapsulation material of the encapsulation area adopts any one of an epoxy group or an isocyanate group (-NCO) or a hydroxyl group (-OH), and the encapsulation material with a modulus suitable for the flexible substrate and capable of being firmly combined with the substrate material is selected to prevent relative sliding, so as to achieve good conformal adhesion. The isocyanate group has a highly unsaturated bond structure with overlapping double bonds, the double bonds and the epoxy group in the flexible encapsulation material crosslink with organic heterocyclic groups (such as imide ring (-CO-NR-CO-)) and active esters in the flexible substrate material, thereby bringing bridging and interpenetration to the free radical reaction system and the epoxy polycondensation system, increasing the crosslinking density of the system. At the same time, the adoption of the multi-functional epoxy in the molecular structure system can effectively improve the interface crosslinking stability between the encapsulation material and the flexible substrate material and the electrode layer material, thereby improving the encapsulation firmness and density.

[0031] Embodiment Two

[0032] A preparation method of an anti-corrosion and waterproof flexible sensor, comprising the following steps:

[0033] S1: cutting a flexible encapsulation material into a pattern required for encapsulation;

[0034] S2: sequentially paste the patterned encapsulation material on the encapsulation area of the electrode layer substrate;

[0035] S3: align and paste the electrode layer substrate with the encapsulation material with the flexible substrate and compact using a roller;

[0036] S4: place the compacted electrode layer substrate and the flexible substrate as a whole under a hot pressing device for hot pressing;

[0037] S5: place the device in a vacuum thermal environment for a certain period of time and then take it out.

[0038] Through the above technical solution, the pre-hot pressing treatment is used first, and then the hot encapsulation process is used in a vacuum environment. The encapsulation material is filled in the grooves in the convex-concave corrugated microstructure under high temperature, and then the interface contact between the flexible encapsulation material and the flexible substrate and the electrode layer is more sufficient under low vacuum environment. The cross-linking reaction occurs between the flexible substrate and the electrode layer material under the thermal environment, and the encapsulation is firm and dense.

[0039] In this embodiment, in step S4, during hot pressing, double-sided hot pressing is performed at a temperature of 80-150 degrees for 5-60 seconds. In step S5, the device is placed in a vacuum thermal environment with a pressure of -0.01 to -1.2 MPa and a temperature of 80 to 150 degrees. In step S5, the device is placed in a vacuum thermal environment for 10-60 minutes and then taken out.

[0040] Specific example 1

[0041] A method for preparing a corrosion and waterproof flexible sensor, a plurality of convex-concave corrugated microstructures with a width-depth ratio of 1.4 and a convex gap of 0.1 mm are made on a polyimide flexible substrate by a flexible printed circuit board process, wherein the corrugation width is 0.1 mm and the corrugation depth is 70 um. The interface between the flexible electrode and the flexible electrode layer is encapsulated by a polyurethane material containing isocyanate groups (-NCO). The encapsulation steps are as follows:

[0042] 1. Cut the flexible encapsulation material (cutting speed 100, power 40) into the required pattern for encapsulation.

[0043] 2. Sequentially paste the patterned encapsulation material on the encapsulation area of the electrode layer substrate.

[0044] 3. Align and paste the electrode layer substrate with the encapsulation material with the flexible substrate and compact using a roller.

[0045] 4. Place the compacted electrode layer substrate and the flexible substrate as a whole under a hot pressing device, and perform double-sided hot pressing at a temperature of 100 degrees for 20 seconds.

[0046] 5. Place the device in a vacuum thermal environment with a vacuum degree of -0.1 MPa and a temperature of 140°C for 30 minutes and then take it out.

[0047] Example 2

[0048] A number of parallel arranged convex-concave ridge microstructures with a width-depth ratio of 83.3 and a ridge gap of 1 mm, wherein the ridge width is 1 mm and the ridge depth is 12 um, are made on a polyimide flexible substrate by a flexible printed circuit board process. The interface between the flexible electrode and the flexible electrode layer is encapsulated with epoxy hydrocarbon resin material, and the encapsulation process steps are as follows:

[0049] 1. The flexible encapsulation material is cut (cutting rate 100, power 40) into the required pattern for encapsulation.

[0050] 2. The patterned encapsulation material is sequentially attached to the encapsulation area of the electrode layer substrate.

[0051] 3. The electrode layer substrate with encapsulation material attached is aligned and attached to the flexible substrate and compacted using a roller.

[0052] 4. The compacted electrode layer substrate and flexible substrate are placed as a whole under a hot pressing device, and double-sided hot pressing is performed at a temperature of 80 degrees for 40 seconds.

[0053] 5. The device is placed in a vacuum degree of -1 MPa, 130°C thermal environment for 40 minutes and then taken out.

[0054] The implementation effect of the above-mentioned example 1 and example 2: the sensor is immersed in 1 meter deep tap water for more than 120 days, there is no liquid immersion and the appearance is perfect, the shear strength test is >1.5 kg / cm 2 , can be immersed in a solution with a pH value of 4 for more than 90 days, there is no liquid immersion and the appearance is perfect, the shear strength test is >1.5 kg / cm 2 , can be immersed in a solution with a pH value of 11 for more than 100 days, there is no liquid immersion and the appearance is perfect, the shear strength test is >1.5 kg / cm 2 .

[0055] Comparative example

[0056] The conventional encapsulation method is directly placed in a normal pressure thermal environment of 80-150 degrees for encapsulation, and there is a small amount of non-contact visible to the naked eye between the interface of the flexible substrate and the electrode layer. The sensor is immersed in a solution with a pH value of 4 for 30 days, and a small amount of liquid is found to be immersed, and the shear strength test is <1 kg / cm 2

[0057] The anti-corrosion and waterproof flexible sensor and the preparation method thereof have the following technical advantages: (1) the packaging material with a modulus suitable for the flexible substrate and capable of cross-linking with the substrate and the electrode layer material is selected to realize good conformal adhesion; (2) the innovative design of the packaging microstructure effectively increases the specific surface area between the packaging region and the flexible substrate and the flexible electrode layer, and enhances the packaging compactness between the electrode layers; and (3) the vacuum environment heat pressing treatment packaging process makes the packaging material melt and fully fill in the convex-concave corrugated microstructure, thereby realizing the firm combination between the substrate layer and the electrode layer.

[0058] The anti-corrosion and waterproof flexible sensor and the preparation method thereof have the following technical advantages: (1) the packaging material with a modulus suitable for the flexible substrate and capable of cross-linking with the substrate and the electrode layer material is selected to realize good conformal adhesion; (2) the innovative design of the packaging microstructure effectively increases the specific surface area between the packaging region and the flexible substrate and the flexible electrode layer, and enhances the packaging compactness between the electrode layers; and (3) the vacuum environment heat pressing treatment packaging process makes the packaging material melt and fully fill in the convex-concave corrugated microstructure, thereby realizing the firm combination between the substrate layer and the electrode layer.

[0059] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and are not limited to the above specific embodiments. Various modifications and changes can be made without departing from the scope of the claims. Those skilled in the art should understand that: although the application has been described in detail with reference to the foregoing embodiments, it can still modify the technical solutions recorded in the foregoing embodiments, or replace some or all of the technical features with equivalent replacements; and these modifications or replacements do not make the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method of preparing a corrosion and water resistant flexible sensor, characterized in that, The method comprises the following steps: S1: cutting the flexible packaging material into a pattern required for packaging; S2: sequentially attaching the patterned packaging material to the packaging area of the electrode layer substrate; S3: aligning and attaching the electrode layer substrate with the attached packaging material to the flexible substrate and compacting using a roller; S4: placing the compacted electrode layer substrate and the flexible substrate as a whole under a hot-pressing device for hot-pressing; S5: placing the device in a vacuum thermal environment for a certain period of time and then taking it out; Before step S1, a plurality of parallel or cross-arranged microstructures are made on the flexible substrate of the corrosion-proof and waterproof flexible sensor, the width-depth ratio of the convex ridges in the microstructures is 1.4 to 83.3, and the gap between the convex ridges is 0.1 to 1 mm.

2. The method of claim 1, wherein the method further comprises: In step S4, during hot-pressing, double-sided hot-pressing is performed at a temperature of 80-150 degrees for 5-60 seconds.

3. The method of claim 2, wherein the method further comprises, In step S5, the device is placed in a vacuum thermal environment with a pressure of -0.01 to -1.2 MPa and a temperature of 80 to 150 degrees, and the device is placed in the vacuum thermal environment for 10-60 minutes before being taken out.

Images